Clinical Indication For Imaging Research Articles

Structural MRI Ratios Fail to Distinguish Progressive Supranuclear Palsy From Parkinson Disease in Individual Patients.

Parkinson disease (PD) and progressive supranuclear palsy (PSP) are often difficult to differentiate in the clinic. The MR parkinsonism index (MRPI) has been recommended to assist in making this distinction. We aimed to assess the usefulness of this tool in our real-world practice of movement disorders. We prospectively obtained MRI scans on consecutive patients with movement disorders with a clinical indication for imaging and obtained measures of MRI regions of interest (ROIs) from our neuroradiologists. The authors reviewed all MRI scans and corrected any errors in the original ROI drawings for this analysis. We retrospectively assigned diagnoses using established consensus criteria from progress notes stored in our electronic medical record. We analyzed the data using multinomial logistic regression models and receiver operating curve analysis to determine the predictive accuracy of the MRI ratios. MRI measures and consensus diagnoses were available on 130 patients with PD, 54 with PSP, and 77 diagnosed as other. The out-of-sample prediction error rate of our 5 regression models ranged from 45% to 59%. The average sensitivity and specificity of the 5 models in the testing sample were 53% and 80%, respectively. The positive predictive value of an MRPI ≥13.55 (the published cutoff) in our patients was 79%. These results indicate that MRI measures of brain structures were not effective at predicting diagnosis in individual patients. We conclude that the search for a biomarker that can differentiate PSP from PD must continue.

Abstract 13823: Clinical Presentation Rather Than Imaging Findings Determine Outcomes in Cardiac Sarcoidosis

Background: Cardiac PET and MRI have facilitated increased diagnosis of Cardiac Sarcoidosis (CS). Varied clinical presentations such as advanced heart block, ventricular arrhythmias and heart failure (HF) are initiating this diagnostic pathway but it is unclear if prognosis is dictated by clinical presentation or imaging findings. In our quaternary care center, we conducted a retrospective review of patients diagnosed with CS by cardiac MRI/PET and examined outcomes in relation to imaging findings and clinical presentation. Methods: 223 patients underwent evaluation for suspected CS by cardiac MRI/PET between 2016-2019 and 62 were identified as having CS based on clinical and imaging criteria. We divided this cohort based on their primary clinical indication for imaging- arrhythmia, HF or screening due to history of pulmonary sarcoidosis. Outcome defined as MACE included death, ICD-shock or admission for HF. Results: Study population was predominantly male (65%), Caucasian (79%) with mean age 60±10 years, Referral diagnosis was HF in 37 (59%), arrhythmia (defined as high grade AV block/ventricular arrhythmias) in 15 (25%) and screening in 10 (16%). While there were no differences in the CMRI LGE findings or degree of inflammation by FDG-PET, there was a higher incidence of resting anteroseptal perfusion on PET, with a higher summed rest score in the arrhythmia group (mean 2 vs 0 in other groups; p<0.05). Based on imaging findings, 39% were treated with steroids, 25% with immunosuppressant, 10% were on combination. Over mean follow-up of 3.5 years, there were 26 events- 6 deaths, 10 ICD shocks 10 heart failure admissions. Event-free survival was 53%, 76% and 80% in the arrhythmia, HF and screening groups respectively. In multivariable analysis, a model that included VT presentation (OR 11; p<0.05) and global hypokinesis on PET images (OR 10; p<0.05) had a sensitivity of 86% and specificity of 63% for MACE prediction. Compared to the model, neither Inflammation on FDG-PET or LGE (MRI) predicted outcomes and treatment with steroids and/or immunosuppressant did not alter prognosis. Conclusions: In this single center study of CS, a primary diagnosis of ventricular arrhythmia and global LV systolic dysfunction, regardless of LVEF, had the worst prognosis.

ASNC/AHA/ASE/EANM/HFSA/ISA/SCMR/SNMMI Expert Consensus Recommendations for Multimodality Imaging in Cardiac Amyloidosis: Part 1 of 2-Evidence Base and Standardized Methods of Imaging.

ASNC/AHA/ASE/EANM/HFSA/ISA/SCMR/SNMMI Expert Consensus Recommendations for Multimodality Imaging in Cardiac Amyloidosis: Part 1 of 2-Evidence Base and Standardized Methods of Imaging.

Role of Susceptibility Weighted Magnetic Resonance Imaging in Neurological Diagnosis

Objectives: The role of susceptibilities in a magnetic field can be used for imaging a diverse group of disease patterns in the human body. The objective of this study is to utilize these properties in the spectrum of neurological diseases. Materials and methods: This is a prospective and retrospective study conducted in the department of radio diagnosis, KMC Hospital, Ambedkar Circle in Mangalore. Over a period of 3 years, utilizing 1.5 Tesla magnetic resonance imaging machine on subjects who had come for routine neurological consultation with clinical indications for imaging. 129 patients of any age group with suspected haemorrhage, infarct, trauma, seizures, intracranial infections, intracranial venous thrombosis and vascular malformations were studied. Results: A total of 129 subjects were studied-40 cases of acute stroke,40 cases of haemorrhage, 8 cases with suspected micro haemorrhages, 15 cases of venous thrombosis, 11 cases of calcifications and 14 cases of contrast enhancement manifesting on SWI imaging in the form of varied susceptibilities to clinch the diagnosis and enable appropriate treatment. Conclusion: Susceptibility weighted imaging is an effective and useful diagnostic tool in magnetic resonance imaging diagnosis for a variety of neurological conditions.

16 Variability in lumbar punctures and neuroimaging in infants less than 90 days with acute bacterial meningitis at a provincial children’s hospital in Canada

Abstract Background Bacterial meningitis remains a significant cause of morbidity and mortality in infants, necessitating appropriate and timely investigations and treatment. Despite this, there are no current Canadian practice guidelines outlining the recommended management of infants with bacterial meningitis beyond empiric antimicrobial choice. As bacterial meningitis remains one of the most severe infectious diseases managed by general pediatricians, it warrants an attempt at practice standardization. Objectives The purpose of this study is to review and identify variation in the timing and frequency of lumbar punctures (LPs) and the use of neuroimaging for the management of bacterial meningitis for infants less than 90 days of age at BC Children’s & Women’s Hospital (BCCWH). Design/Methods A retrospective chart review at BCCWH identified confirmed, presumed or possible bacterial meningitis in infants less than 90 days of age over a five-year period (2013-2018). Anonymized data was collected from medical charts, de-identified and stored in REDCap. Results Eighty-one patients were included. Fifty-three percent of all patients had a delay in receiving an initial LP. The most common reasons for delays were that the patient was too unstable (42%) or that the first LP attempt was unsuccessful (26%). Forty-six percent of all patients had only one LP while 36% had at least one repeat LP. Most repeat LPs were done within 7 days of diagnosis. Twenty-nine percent of patients had an end of treatment LPs. Of all patients, 80% had neuroimaging. Head ultrasound (US) was the most commonly used imaging modality for both first image (68%) and subsequent images (64%). Seventeen percent of patients received a CT scan and 15% an MRI as their first image. In most cases, there was no clear clinical indication for imaging noted other than a diagnosis of meningitis (44%). Conclusion This retrospective study confirms that there is variability in the management of bacterial meningitis with respect to lumbar punctures and neuroimaging in young infants. The findings demonstrate LPs are commonly delayed, and suggest a need to develop clearly defined criteria for evaluating instability before an initial LP. Furthermore, the findings raise concern regarding the common practice of ordering head ultrasound for meningitis, given lower sensitivity in detecting disease complications and therefore disputed clinical utility.

ASNC/AHA/ASE/EANM/HFSA/ISA/SCMR/SNMMI Expert Consensus Recommendations for Multimodality Imaging in Cardiac Amyloidosis: Part 1 of 2—Evidence Base and Standardized Methods of Imaging

Cardiac amyloidosis is a form of restrictive infiltrative cardiomyopathy that confers significant mortality. Because of the relative rarity of cardiac amyloidosis, clinical and diagnostic expertise in the recognition and evaluation of individuals with suspected amyloidosis is mostly limited to a few expert centers. Electrocardiography, echocardiography, and radionuclide imaging have been used for the evaluation of cardiac amyloidosis for over 40 years. 1 Child J.S. Levisman J.A. Abbasi A.S. MacAlpin R.N. Echocardiographic manifestations of infiltrative cardiomyopathy: a report of seven cases due to amyloid. Chest. 1976; 70: 726-731 Abstract Full Text Full Text PDF PubMed Google Scholar , 2 Braun S.D. Lisbona R. Novales-Diaz J.A. Sniderman A. Myocardial uptake of 99mTc-phosphate tracer in amyloidosis. Clin Nucl Med. 1979; 4: 244-245 Crossref PubMed Google Scholar , 3 Gillmore J.D. Maurer M.S. Falk R.H. Merlini G. Damy T. Dispenzieri A. et al. Nonbiopsy diagnosis of cardiac transthyretin amyloidosis. Circulation. 2016; 133: 2404-2412 Crossref PubMed Google Scholar Although cardiovascular magnetic resonance (CMR) has also been in clinical practice for several decades, it was not applied to cardiac amyloidosis until the late 1990s. Despite an abundance of diagnostic imaging options, cardiac amyloidosis remains largely underrecognized or delayed in diagnosis. 4 Alexander K.M. Orav J. Singh A. Jacob S.A. Menon A. Padera R.F. et al. Geographic disparities in reported US amyloidosis mortality from 1979 to 2015: potential underdetection of cardiac amyloidosis. JAMA Cardiol. 2018; 3: 865-870 Crossref PubMed Scopus (7) Google Scholar Although advanced imaging options for noninvasive evaluation have substantially expanded, the evidence is predominately confined to single-center small studies or limited multicenter larger experiences, and there continues to be no clear consensus on standardized imaging pathways in cardiac amyloidosis. This lack of guidance is particularly problematic given that there are numerous emerging therapeutic options for this morbid disease, increasing the importance of accurate recognition at earlier stages. Imaging provides noninvasive tools for follow-up of disease remission/progression complementing clinical evaluation. Additional areas not defined include appropriate clinical indications for imaging, optimal imaging utilization by clinical presentation, accepted imaging methods, accurate image interpretation, and comprehensive and clear reporting. Prospective randomized clinical trial data for the diagnosis of amyloidosis and for imaging-based strategies for treatment are not available. A consensus of expert opinion is greatly needed to guide the appropriate clinical utilization of imaging in cardiac amyloidosis.

Risk of ESRD and Mortality in Kidney and Bladder Stone Formers

Kidney stones have been associated with increased risk for end-stage renal disease (ESRD). However, it is unclear whether there is also an increased risk for mortality and if these risks are uniform across clinically distinct categories of stone formers. Historical matched-cohort study. Stone formers in OlmstedCounty, MN, between 1984 and 2012 identified using International Classification of Diseases, Ninth Revision codes. Age- and sex-matched individuals who had no codes for stones were the comparison group. Stone formers were placed into 5 mutually exclusive categories after review of medical charts: incident symptomatic kidney, recurrent symptomatic kidney, asymptomatic kidney, bladder only, and miscoded (no stone). ESRD, mortality, cardiovascular mortality, and cancer mortality. Cox proportional hazards models with adjustment for baseline comorbid conditions. Overall, 65 of 6,984 (0.93%) stone formers and 102 of 28,044 (0.36%) non-stone formers developed ESRD over a mean follow-up of 12.0 years. After adjusting for baseline hypertension, diabetes mellitus, dyslipidemia, gout, obesity, and chronic kidney disease, risk for ESRD was higher in recurrent symptomatic kidney (HR, 2.34; 95% CI, 1.08-5.07), asymptomatic kidney (HR, 3.94; 95% CI, 1.65-9.43), and miscoded (HR, 6.18; 95% CI, 2.25-16.93) stone formers, but not in incident symptomatic kidney or bladder stone formers. The adjusted risk for all-cause mortality was higher in asymptomatic kidney (HR, 1.40; 95% CI, 1.18-1.67) and bladder (HR, 1.37; 95% CI, 1.12-1.69) stone formers. Chart review of asymptomatic and miscoded stone formers suggested increased risk for adverse outcomes related to diagnoses including urinary tract infection, cancer, and musculoskeletal or gastrointestinal pain. The higher risk for ESRD in recurrent symptomatic compared with incident symptomatic kidney stone formers suggests that stone events are associated with kidney injury. The clinical indication for imaging in asymptomatic stone formers, the correct diagnosis in miscoded stone formers, and the cause of a bladder outlet obstruction in bladder stone formers may explain the higher risk for ESRD or death in these groups.

An audit of clinical practice, referral patterns, and appropriateness of clinical indications for brain MRI examinations: A single-centre study in Ghana

IntroductionThe aim of this study was to investigate current brain MRI practice, pattern of brain MRI requests, and their appropriateness using the American College of Radiology (ACR) Appropriateness Criteria. Material and methodsWe used direct observation and questionnaires to obtain data concerning routine brain MRI practice. We then retrospectively analyzed (i) demographic characteristics, (ii) clinical history, and (iii) appropriateness of brain MRI requests against published criteria. ResultsAll patients were administered the screening questionnaire; however, no reviews were undertaken directly with patients, and no signature of the radiographer was recorded. Apart from routine brain protocol, there were dedicated protocols for epilepsy and stroke. Brain MRI images from 161 patients (85 Males; 76 Females) were analyzed. The age group with most brain MRI requests were from 26 to 45 year olds. The commonest four clinical indications for imaging were brain tumour, headache, seizure, and stroke. Using the ACR Appropriateness Criteria, almost 43% of the brain MRI scans analyzed were found to be “usually appropriate”, 38% were “maybe appropriate” and 19% were categorized as “usually not appropriate”. ConclusionThere was knowledge gap with regards to MRI safety in local practice, thus there is the utmost need for MRI safety training. Data on the commonest indications for performing brain MRI in this study should be used to inform local neuroradiological practice. Dedicated stroke and epilepsy MRI protocols require additional sequences i.e. MRA and 3D T1 volume acquisition, respectively. The ACR Appropriateness Criteria is recommended for use by the referring practitioners to improve appropriateness of brain MRI requests.

Changes in cardiovascular medication after coronary artery calcium scanning and normal single photon emission computed tomography myocardial perfusion imaging in symptomatic patients

In the current study, 1,033 stable symptomatic patients without a known history of coronary artery disease with normal SPECT MPI who underwent concomitant CAC scoring were included. All patients had a clinical indication for imaging, mainly atypical chest pain and dyspnea, and were referred from the outpatient clinic of our hospital. Data regarding posttest medication change (either starting or discontinuation of aspirin and statin therapy at the subsequent outpatient visit) were retrospectively collected. Patients were categorized into 4 groups based on their CAC score. Mean age of the patients was 61±11 years and 39% were male. At baseline, 35% of the patients used aspirin and 39% used statin. In patients with CAC scores 0, 1-99, 100-399, and ≥400, aspirin was started in 1%, 4%, 9%, and 9%, respectively, and statin was started in 0%, 7%, 18%, and 24% of the patients, respectively (P<.001). Aspirin was discontinued in 19%, 11%, 7%, and 1% and statin was discontinued in 8%, 6%, 2%, and 0% (P<.001) of the patients in these respective CAC score categories. After correction for differences in risk factors and baseline medication use, increased CAC was independently associated with posttest aspirin (odds ratio 4.6, 11.2, and 27.1 for CAC scores 1-99, 100-399, and ≥400, respectively; P<.001) and statin use (odds ratio 4.4, 19.4, and 60.9 for CAC scores 1-99, 100-399, and ≥400, respectively; P<.001). Higher CAC scores are associated with the initiation of aspirin and statin therapy in patients with normal SPECT MPI. In patients with lower CAC scores, discontinuation of cardioprotective medication is more likely. CAC score is independently associated with posttest statin and aspirin use.

Radiological imaging in the spine

Abstract The spine is a complex structure that comprises multiple joints and soft tissue elements that in concert allow weight bearing and function. There are numerous clinical indications for imaging in the spine; 'back' pain and neurological symptoms are the most common presenting complaints with a wide variety of disorders that could contribute to symptoms. This article will outline important spinal pathologies and illustrate how imaging plays a pivotal role in their assessment and management.

Contrast-enhanced ultrasound using SonoVue® (sulphur hexafluoride microbubbles) compared with contrast-enhanced computed tomography and contrast-enhanced magnetic resonance imaging for the characterisation of focal liver lesions and detection of liver metastases: a systematic review and cost-effectiveness analysis

BACKGROUND: Medical imaging techniques are important in the management of many patients with liver disease. Unenhanced ultrasound examinations sometimes identify focal abnormalities in the liver that may require further investigation, primarily to distinguish liver cancers from benign abnormalities. One important factor in selecting an imaging test is the ability to provide a rapid diagnosis. Options for additional imaging investigations include computed tomography (CT) and/or magnetic resonance imaging (MRI) and biopsy when the diagnosis remains uncertain. CT and MRI usually require referral with associated waiting time and are sometimes contraindicated. The use of contrast agents may improve the ability of ultrasound to distinguish between liver cancer and benign abnormalities and, because it can be performed at the same appointment as unenhanced ultrasound, more rapid diagnoses may be possible. OBJECTIVE: To compare the clinical effectiveness and cost-effectiveness of contrast-enhanced ultrasound (CEUS) using SonoVue((R)) with that of contrast-enhanced computed tomography (CECT) and contrast-enhanced magnetic resonance imaging (CEMRI) for the assessment of adults with focal liver lesions (FLLs) in whom previous liver imaging is inconclusive. DATA SOURCES: Eight bibliographic databases including MEDLINE, EMBASE, Cochrane Database of Systematic Reviews and Database of Abstracts of Reviews of Effects were searched from 2000 to September/October 2011. Research registers and conference proceedings were also searched. REVIEW METHODS: Systematic review methods followed published guidance. Risk of bias was assessed using a modified version of the QUADAS-2 tool. Results were stratified by clinical indication for imaging (characterisation of FLLs detected on ultrasound surveillance of cirrhosis patients, detection of liver metastases, characterisation of incidentally detected FLLs, assessment of treatment response). For incidental FLLs, pooled estimates of sensitivity and specificity, with 95% CIs, were calculated using a random-effects model. For other clinical indications a narrative summary was used. The cost-effectiveness of CEUS was modelled separately for the three main clinical applications considered [characterisation of FLLs detected on ultrasound surveillance of cirrhosis patients, detection of liver metastases in patients with colorectal cancer (CRC), characterisation of incidentally detected FLLs]. RESULTS: Of the 854 references identified, 19 (describing 18 studies) were included in the review. Hand searching of conference proceedings identified a further three studies. Twenty of the 21 studies included in the systematic review were diagnostic test accuracy studies. Studies in cirrhosis patients reported varying estimates of test performance. There was no consistent evidence of a significant difference in performance between imaging modalities. It was unclear whether or not CEUS alone is adequate to rule out hepatocellular carcinoma (HCC) for FLLs of < 30 mm; one study indicated that CEUS may be better at ruling out HCC for FLLs of 11-30 mm [very small FLLs (< 10 mm) excluded]. There was no consistent evidence of a difference in test performance between imaging modalities for the detection of metastases; CEUS alone may be adequate to rule out liver metastases in colorectal cancer. In patients with incidentally detected FLLs, the pooled estimates of sensitivity for any malignancy using CEUS and CECT were 95.1% and 94.6%, respectively, and the corresponding specificity estimates were 93.8% and 93.1% respectively. One study comparing CEUS with CEMRI reported similar sensitivity and lower specificity for both modalities. In the surveillance of cirrhosis, CEUS was as effective as but pound379 less costly than CECT. CEMRI was pound1063 more costly than CEUS and gained 0.022 QALYs. In the detection of liver metastases from CRC, CEUS cost pound1 more than CECT, and at a lifetime time horizon they yielded equal QALYs. CEMRI was dominated by CECT. In the characterisation of incidentally detected FLLs, CEUS was slightly more effective than CECT and CEMRI (by 0.0002 QALYs and 0.0026 QALYs respectively) and less costly (by pound52 and pound131 respectively). LIMITATIONS: There were a number of methodological issues specific to the studies included in this review. The main indication for liver imaging in the populations considered is likely to be to rule out primary liver cancer or metastases. Therefore, patient-level analyses of test performance are of particular interest. Some of the studies included in this review reported per-patient analyses; however, no study clearly stated how results were defined (e.g. was the presence of any positive lesion regarded as a positive test for the whole patient). In addition,

Interventional radiology in renal trauma

Injury to the kidney is relatively common in significant abdominal trauma with the majority of injuries being secondary to a blunt rather than penetrating mechanism. Iatrogenic injury is an important additional cause of renal vascular damage. Multidetector computed tomography (CT) is the reference imaging modality in patients with suspected blunt, penetrating or iatrogenic injury. It allows rapid acquisition of images that accurately identify and stage injury to the kidneys and other major organs. This review addresses clinical indications for imaging, injury classification and the subsequent management of renal trauma, focusing on the important role of the interventional radiology team, particularly in stopping life-threatening haemorrhage by transcatheter embolisation techniques.

Indications for Orbital Imaging by the Oculoplastic Surgeon

To determine the indications for ordering orbital imaging and the indications for ordering CT versus MRI by oculoplastic surgeons and to assess the correlation between surgeon's clinical indications for imaging and the radiologist's diagnosis. Retrospective review of imaging requisitions and radiology reports. Patients of 4 oculoplastic surgeons who required CT or MRI scans. Imaging requisitions and radiology reports of patients from 4 oculoplastic surgeons were reviewed to determine the indication for ordering a CT or MRI scan between March 2006 and March 2009. The indications were then compared with the radiologist's diagnosis. A total of 735 patients were included: 449 (61.1%) female and 286 (38.9%) male, with an average age of 50.1 years and an age range of 7 months to 93 years. Of these patients, a total of 632 CT and 223 MRI scans were ordered, 135 of which were follow-up scans. The most common indication for CT scan was thyroid disease, followed by orbital tumors and then inflammatory disease, while the most common indication for MRI scan was orbital tumors, followed by inflammatory disease and then thyroid disease. CT scans were more commonly ordered than MRI, largely for trauma and to rule out orbital foreign body.

Analysis of adherence to published guidelines for vestibular schwannoma screening: Correlating published guidelines to diagnostic yield

Analysis of adherence to published guidelines for vestibular schwannoma screening: Correlating published guidelines to diagnostic yield

Late magnetic resonance surveillance of repaired coarctation of the aorta☆☆☆

Objective: Coarctation of the aorta has often been described as a simple form of congenital heart disease. However, rates of re-coarctation reported in the literature vary from 7% to 60%. Re-coarctation of the aorta may lead to worsening systemic hypertension, coronary artery disease and/or congestive cardiac failure. We aimed to describe the rates of re-coarctation in subjects who had undergone early coarctation repair (<2 years of age) and referred for clinically indicated or routine magnetic resonance (MR) surveillance. Methods: We retrospectively identified 50 consecutive subjects (20.2 ± 6.9 years post-repair) imaged between 2004 and 2008. Patient characteristics, rates of re-coarctation and LV/aortic dimensions were examined. Results: Forty percent of subjects had bicuspid aortic valves (BAV). There were 40 cases of end-to-end repair and 10 cases of subclavian flap repair. Re-intervention with balloon angioplasty or repeat surgery had been performed in 32% of subjects. The MRI referrals were clinically indicated in 34% and routine in 66% of patients. Re-coarctation was considered moderate or severe in 34%, mild in 34% and no re-coarctation was identified in 32% of patients. There was no significant difference in the number of cases of re-coarctation identified in the clinically indicated versus routine referrals for MR imaging (p = 0.20). There were no cases of aortic dissection or aneurysm formation identified amongst the subjects. The mean indexed left ventricular mass and ejection fraction was 72 ± 16 g/m2 and 66 ± 6%, respectively. Amongst those subjects with BAV there were larger aortic sinus (30 ± 1 mm vs 27 ± 1 mm, p = 0.03) and ascending aortic (27 ± 1 mm vs 23 ± 1 mm, p = 0.01) dimensions when compared to subjects with morphologically tricuspid aortic valves. Conclusions: We demonstrate that many years after early repair of coarctation of the aorta, MR surveillance detects significant rates of re-coarctation. These findings were independent of whether or not there was a clinical indication for imaging. Those patients with BAV disease had larger ascending aortic dimensions and may require more frequent non-invasive surveillance.

MR imaging assessment of the lateral head of the gastrocnemius muscle: prevalence of segmental anomalous origins in children and young adults

Variations in the lower extremity musculature have been identified, including an anomalous origin of the medial head of the gastrocnemius muscle. Anomalies of the lateral head of the gastrocnemius muscle (LGN) have been less frequently described, especially in children. To describe the MR imaging appearance, frequency and clinical symptoms associated with anatomic variations of the LGN in children and young adults. A retrospective review of 465 knee MR imaging examinations was performed. The site of origin of the LGN was identified as either normal, lateral segmental anomalous origin (LSAO), or medial accessory anomalous origin (MAAO). The clinical indication for imaging was recorded. An anatomic variation of the LGN was identified in 16 patients (3.4%). Nine patients had LSAO, and five of these had symptoms referable to or abnormalities of the patella. Seven patients had MAAO, and three of these had chronic nontraumatic knee pain. Anatomic variations of the LGN are not rare in young patients, occurring with a frequency of 3.4% in our series. It is unknown whether these anomalies play a role in the etiology of patellofemoral pain or unexplained joint pain in children.

American College of Radiology White Paper on Radiation Dose in Medicine

The benefits of diagnostic imaging are immense and have revolutionized the practice of medicine. The increased sophistication and clinical efficacy of imaging have resulted in its dramatic growth over the past quarter century. Although data derived from the atomic bomb survivors in Japan and other events suggest that the expanding use of imaging modalities using ionizing radiation may eventually result in an increased incidence of cancer in the exposed population, this problem can likely be minimized by preventing the inappropriate use of such imaging and by optimizing studies that are performed to obtain the best image quality with the lowest radiation dose. The ACR, which has been an advocate for radiation safety since its inception in 1924, convened the ACR Blue Ribbon Panel on Radiation Dose in Medicine to address these issues. This white paper details a proposed action plan for the college derived from the deliberations of that panel.

NUCLEAR MEDICINE IMAGING OF LUNG CANCER

Although nuclear medicine imaging is still widely under-appreciated and underused by the medical and radiologic communities, FDG PET imaging and Tc 99m depreotide SPECT imaging are safe, cost-effective methods with advantages over CT and other imaging methods in the diagnosis and management of patients suspected or known to have lung cancer. Physicians involved in the care of these patients should familiarize themselves with both of these relatively new nuclear medicine imaging procedures. Both F-18 FDG PET imaging and Tc 99m depreotide SPECT imaging have a high degree of sensitivity, specificity, overall accuracy, and both PPV and NPV in the management of patients with a solitary pulmonary nodule. Nuclear imaging with either of these agents provides a noninvasive, cost-effective method to select patients for aggressive intervention without contributing to increased morbidity. There has not been a direct comparison of these two techniques in terms of their relative role and cost-effectiveness in the management of patients with a solitary pulmonary nodule. Both methods have incremental value over CT imaging in selecting patients with solitary pulmonary nodules either for invasive biopsy or for thoracotomy. To date, only FDG PET has been proved to have additional application in: 1. Improving the staging of patients by identifying or excluding mediastinal disease. Some authors are reluctant at the present time to deny patients an opportunity for curative resection based on the finding of foci of increased metabolism in the mediastinum (characterized by increased FDG activity) because there are occasional false-positive studies. They propose, however, that a negative study justifies a surgical approach (and an opportunity for cure) regardless of the findings on CT. 2. Evaluation of therapy and early detection of recurrence by using FDG PET imaging as a monitoring procedure. Tc 99m depreotide may have a role also in these other clinical indications for imaging in patients with lung carcinoma. It is too soon, however, to know if Tc 99m depreotide SPECT imaging, properly performed, can mimic the success of FDG PET in the detection or exclusion of mediastinal metastases, evaluating the response to therapy, and the early detection of recurrent disease during post-therapeutic monitoring.